cmd/setexpr.c

   1 /*
   2  * Copyright 2008 Freescale Semiconductor, Inc.
   3  * Copyright 2013 Wolfgang Denk <wd@denx.de>
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 /*
   9  * This file provides a shell like 'expr' function to return.
  10  */
  11
  12 #include <common.h>
  13 #include <config.h>
  14 #include <command.h>
  15 #include <mapmem.h>
  16
  17 static ulong get_arg(char *s, int w)
  18 {
  19         /*
  20          * If the parameter starts with a '*' then assume it is a pointer to
  21          * the value we want.
  22          */
  23         if (s[0] == '*') {
  24                 ulong *p;
  25                 ulong addr;
  26                 ulong val;
  27
  28                 addr = simple_strtoul(&s[1], NULL, 16);
  29                 switch (w) {
  30                 case 1:
  31                         p = map_sysmem(addr, sizeof(uchar));
  32                         val = (ulong)*(uchar *)p;
  33                         unmap_sysmem(p);
  34                         return val;
  35                 case 2:
  36                         p = map_sysmem(addr, sizeof(ushort));
  37                         val = (ulong)*(ushort *)p;
  38                         unmap_sysmem(p);
  39                         return val;
  40                 case 4:
  41                 default:
  42                         p = map_sysmem(addr, sizeof(ulong));
  43                         val = *p;
  44                         unmap_sysmem(p);
  45                         return val;
  46                 }
  47         } else {
  48                 return simple_strtoul(s, NULL, 16);
  49         }
  50 }
  51
  52 #ifdef CONFIG_REGEX
  53
  54 #include <slre.h>
  55
  56 #define SLRE_BUFSZ      16384
  57 #define SLRE_PATSZ      4096
  58
  59 /*
  60  * memstr - Find the first substring in memory
  61  * @s1: The string to be searched
  62  * @s2: The string to search for
  63  *
  64  * Similar to and based on strstr(),
  65  * but strings do not need to be NUL terminated.
  66  */
  67 static char *memstr(const char *s1, int l1, const char *s2, int l2)
  68 {
  69         if (!l2)
  70                 return (char *)s1;
  71
  72         while (l1 >= l2) {
  73                 l1--;
  74                 if (!memcmp(s1, s2, l2))
  75                         return (char *)s1;
  76                 s1++;
  77         }
  78         return NULL;
  79 }
  80
  81 static char *substitute(char *string,   /* string buffer */
  82                         int *slen,      /* current string length */
  83                         int ssize,      /* string bufer size */
  84                         const char *old,/* old (replaced) string */
  85                         int olen,       /* length of old string */
  86                         const char *new,/* new (replacement) string */
  87                         int nlen)       /* length of new string */
  88 {
  89         char *p = memstr(string, *slen, old, olen);
  90
  91         if (p == NULL)
  92                 return NULL;
  93
  94         debug("## Match at pos %ld: match len %d, subst len %d\n",
  95                 (long)(p - string), olen, nlen);
  96
  97         /* make sure replacement matches */
  98         if (*slen + nlen - olen > ssize) {
  99                 printf("## error: substitution buffer overflow\n");
 100                 return NULL;
 101         }
 102
 103         /* move tail if needed */
 104         if (olen != nlen) {
 105                 int tail, len;
 106
 107                 len = (olen > nlen) ? olen : nlen;
 108
 109                 tail = ssize - (p + len - string);
 110
 111                 debug("## tail len %d\n", tail);
 112
 113                 memmove(p + nlen, p + olen, tail);
 114         }
 115
 116         /* insert substitue */
 117         memcpy(p, new, nlen);
 118
 119         *slen += nlen - olen;
 120
 121         return p + nlen;
 122 }
 123
 124 /*
 125  * Perform regex operations on a environment variable
 126  *
 127  * Returns 0 if OK, 1 in case of errors.
 128  */
 129 static int regex_sub(const char *name,
 130         const char *r, const char *s, const char *t,
 131         int global)
 132 {
 133         struct slre slre;
 134         char data[SLRE_BUFSZ];
 135         char *datap = data;
 136         const char *value;
 137         int res, len, nlen, loop;
 138
 139         if (name == NULL)
 140                 return 1;
 141
 142         if (slre_compile(&slre, r) == 0) {
 143                 printf("Error compiling regex: %s\n", slre.err_str);
 144                 return 1;
 145         }
 146
 147         if (t == NULL) {
 148                 value = getenv(name);
 149
 150                 if (value == NULL) {
 151                         printf("## Error: variable \"%s\" not defined\n", name);
 152                         return 1;
 153                 }
 154                 t = value;
 155         }
 156
 157         debug("REGEX on %s=%s\n", name, t);
 158         debug("REGEX=\"%s\", SUBST=\"%s\", GLOBAL=%d\n",
 159                 r, s ? s : "<NULL>", global);
 160
 161         len = strlen(t);
 162         if (len + 1 > SLRE_BUFSZ) {
 163                 printf("## error: subst buffer overflow: have %d, need %d\n",
 164                         SLRE_BUFSZ, len + 1);
 165                 return 1;
 166         }
 167
 168         strcpy(data, t);
 169
 170         if (s == NULL)
 171                 nlen = 0;
 172         else
 173                 nlen = strlen(s);
 174
 175         for (loop = 0;; loop++) {
 176                 struct cap caps[slre.num_caps + 2];
 177                 char nbuf[SLRE_PATSZ];
 178                 const char *old;
 179                 char *np;
 180                 int i, olen;
 181
 182                 (void) memset(caps, 0, sizeof(caps));
 183
 184                 res = slre_match(&slre, datap, len, caps);
 185
 186                 debug("Result: %d\n", res);
 187
 188                 for (i = 0; i < slre.num_caps; i++) {
 189                         if (caps[i].len > 0) {
 190                                 debug("Substring %d: [%.*s]\n", i,
 191                                         caps[i].len, caps[i].ptr);
 192                         }
 193                 }
 194
 195                 if (res == 0) {
 196                         if (loop == 0) {
 197                                 printf("%s: No match\n", t);
 198                                 return 1;
 199                         } else {
 200                                 break;
 201                         }
 202                 }
 203
 204                 debug("## MATCH ## %s\n", data);
 205
 206                 if (s == NULL) {
 207                         printf("%s=%s\n", name, t);
 208                         return 1;
 209                 }
 210
 211                 old = caps[0].ptr;
 212                 olen = caps[0].len;
 213
 214                 if (nlen + 1 >= SLRE_PATSZ) {
 215                         printf("## error: pattern buffer overflow: have %d, need %d\n",
 216                                 SLRE_BUFSZ, nlen + 1);
 217                         return 1;
 218                 }
 219                 strcpy(nbuf, s);
 220
 221                 debug("## SUBST(1) ## %s\n", nbuf);
 222
 223                 /*
 224                  * Handle back references
 225                  *
 226                  * Support for \0 ... \9, where \0 is the
 227                  * whole matched pattern (similar to &).
 228                  *
 229                  * Implementation is a bit simpleminded as
 230                  * backrefs are substituted sequentially, one
 231                  * by one.  This will lead to somewhat
 232                  * unexpected results if the replacement
 233                  * strings contain any \N strings then then
 234                  * may get substitued, too.  We accept this
 235                  * restriction for the sake of simplicity.
 236                  */
 237                 for (i = 0; i < 10; ++i) {
 238                         char backref[2] = {
 239                                 '\\',
 240                                 '0',
 241                         };
 242
 243                         if (caps[i].len == 0)
 244                                 break;
 245
 246                         backref[1] += i;
 247
 248                         debug("## BACKREF %d: replace \"%.*s\" by \"%.*s\" in \"%s\"\n",
 249                                 i,
 250                                 2, backref,
 251                                 caps[i].len, caps[i].ptr,
 252                                 nbuf);
 253
 254                         for (np = nbuf;;) {
 255                                 char *p = memstr(np, nlen, backref, 2);
 256
 257                                 if (p == NULL)
 258                                         break;
 259
 260                                 np = substitute(np, &nlen,
 261                                         SLRE_PATSZ,
 262                                         backref, 2,
 263                                         caps[i].ptr, caps[i].len);
 264
 265                                 if (np == NULL)
 266                                         return 1;
 267                         }
 268                 }
 269                 debug("## SUBST(2) ## %s\n", nbuf);
 270
 271                 datap = substitute(datap, &len, SLRE_BUFSZ,
 272                                 old, olen,
 273                                 nbuf, nlen);
 274
 275                 if (datap == NULL)
 276                         return 1;
 277
 278                 debug("## REMAINDER: %s\n", datap);
 279
 280                 debug("## RESULT: %s\n", data);
 281
 282                 if (!global)
 283                         break;
 284         }
 285         debug("## FINAL (now env_set()) :  %s\n", data);
 286
 287         printf("%s=%s\n", name, data);
 288
 289         return env_set(name, data);
 290 }
 291 #endif
 292
 293 static int do_setexpr(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 294 {
 295         ulong a, b;
 296         ulong value;
 297         int w;
 298
 299         /*
 300          * We take 3, 5, or 6 arguments:
 301          * 3 : setexpr name value
 302          * 5 : setexpr name val1 op val2
 303          *     setexpr name [g]sub r s
 304          * 6 : setexpr name [g]sub r s t
 305          */
 306
 307         /* > 6 already tested by max command args */
 308         if ((argc < 3) || (argc == 4))
 309                 return CMD_RET_USAGE;
 310
 311         w = cmd_get_data_size(argv[0], 4);
 312
 313         a = get_arg(argv[2], w);
 314
 315         /* plain assignment: "setexpr name value" */
 316         if (argc == 3) {
 317                 setenv_hex(argv[1], a);
 318                 return 0;
 319         }
 320
 321         /* 5 or 6 args (6 args only with [g]sub) */
 322 #ifdef CONFIG_REGEX
 323         /*
 324          * rexep handling: "setexpr name [g]sub r s [t]"
 325          * with 5 args, "t" will be NULL
 326          */
 327         if (strcmp(argv[2], "gsub") == 0)
 328                 return regex_sub(argv[1], argv[3], argv[4], argv[5], 1);
 329
 330         if (strcmp(argv[2], "sub") == 0)
 331                 return regex_sub(argv[1], argv[3], argv[4], argv[5], 0);
 332 #endif
 333
 334         /* standard operators: "setexpr name val1 op val2" */
 335         if (argc != 5)
 336                 return CMD_RET_USAGE;
 337
 338         if (strlen(argv[3]) != 1)
 339                 return CMD_RET_USAGE;
 340
 341         b = get_arg(argv[4], w);
 342
 343         switch (argv[3][0]) {
 344         case '|':
 345                 value = a | b;
 346                 break;
 347         case '&':
 348                 value = a & b;
 349                 break;
 350         case '+':
 351                 value = a + b;
 352                 break;
 353         case '^':
 354                 value = a ^ b;
 355                 break;
 356         case '-':
 357                 value = a - b;
 358                 break;
 359         case '*':
 360                 value = a * b;
 361                 break;
 362         case '/':
 363                 value = a / b;
 364                 break;
 365         case '%':
 366                 value = a % b;
 367                 break;
 368         default:
 369                 printf("invalid op\n");
 370                 return 1;
 371         }
 372
 373         setenv_hex(argv[1], value);
 374
 375         return 0;
 376 }
 377
 378 U_BOOT_CMD(
 379         setexpr, 6, 0, do_setexpr,
 380         "set environment variable as the result of eval expression",
 381         "[.b, .w, .l] name [*]value1 <op> [*]value2\n"
 382         "    - set environment variable 'name' to the result of the evaluated\n"
 383         "      expression specified by <op>.  <op> can be &, |, ^, +, -, *, /, %\n"
 384         "      size argument is only meaningful if value1 and/or value2 are\n"
 385         "      memory addresses (*)\n"
 386         "setexpr[.b, .w, .l] name [*]value\n"
 387         "    - load a value into a variable"
 388 #ifdef CONFIG_REGEX
 389         "\n"
 390         "setexpr name gsub r s [t]\n"
 391         "    - For each substring matching the regular expression <r> in the\n"
 392         "      string <t>, substitute the string <s>.  The result is\n"
 393         "      assigned to <name>.  If <t> is not supplied, use the old\n"
 394         "      value of <name>\n"
 395         "setexpr name sub r s [t]\n"
 396         "    - Just like gsub(), but replace only the first matching substring"
 397 #endif
 398 );